Minnesota paleontology and geology, National Park Service paleontology, the Mesozoic, and occasional distractions

Tuesday, May 23, 2017

When to stay away from outcrops and exposures

Some recent events have provided photographic fodder for a brief unscheduled revisit of safety concerns in the rocks of the Twin Cities, but first I am going to plug the reborn Park Paleontology newsletter. I'll hit it some more this weekend in more detail, but I particularly want to call out Chapter 3 by Emily Thorpe, who was a Geoscientists in the Parks intern over the winter at Salinas Pueblo Missions National Monument. Among other discoveries, she's got the first vertebrate from the Yeso Group (Arroyo de Alamillo Formation), the part and counterpart articulated back half of a skeleton. We've had a lot of great projects from GIPs the past few years, and I'd strongly encourage college students in the geosciences to have a look when the next batch of positions comes out.

Meanwhile, back in the Ordovician...

You may remember the following photo from this post, or this post. Coincidentally, in both posts the photo is being used as an example of a hazard. It was taken back in June 2013 along the road into Crosby Farm Regional Park, before you get to Watergate Marina.

I wonder where this is going...

If you take that road today (May 2017), this is what you'll see:

...the answer appears to be "down".

This is why you should not stand too close to the walls of the bluffs, or to the edge on top.

Meanwhile, over at Shadow Falls, the Decorah Shale presents a different issue, one that can be expressed as a recipe titled "Reconstituted Ordovician Seafloor": take a hillslope of weathered marine shale, and over the course of six days add nearly five inches of rain. It's amazing!

Hiking boots? More like cleats.

The running water is Nature's subtle way of telling you to stay off.

It's not the mud itself that's the big problem (unless you hate mud, in which case you're really in the wrong place), but the slippery sloppy footing. If you go over into the ravine, it's not going to be easy to get you out!